High output is required for a light emitting diode (LED) used for an illumination device, a display device, a traffic signal, a sensor device and the like.
In the case of an LED with a reflective metal in which light emitted downward from a light emitting layer is reflected upward by the reflective metal layer, light extraction efficiency can be improved.
However, if a current injected from an electrode on the reflective metal layer side is, for example, too much spread laterally, an effective current injection density in the light emitting layer decreases, resulting in a reduction of the light emission efficiency. Therefore, it becomes difficult to achieve higher optical output.